As your information is lacking model then go to www.thetford-europe.com and look up your model and if the bench type C2 post this on answer sheet to your question. Three days I'll check, after I'll not bother and assume you've done it.
bob
March 2011
Automatic Answer
While you wait for answers, we may have found some information which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix caravans/motorhomes.